Hammer mill



Nov. 23, 1965 J. c. COLE 3,219,285

HAMMER MILL Filed April 22, 1963 2 Sheets-Sheet l INVENTOR. JEREMY C. COLE i /Z44 6 g /M A T TORNEVS Nov. 23, 1965 J. c. COLE 3,219,285

HAMMER MILL Filed April 22, 1963 2 Sheets-Sheet 2 9 INVENTOR LK JEREMY C. COLE AT TOP/VEVS United States Patent F 3,219,285 HAMMER MILL Jeremy C. Cole, San Francisco, Calif, assignor, by mesne assignments, to Arthur G. McKee & Company, San Francisco, Calif.

Filed Apr. 22, 1963. Ser. No. 274,592 2 Claims. (Cl. 241-76) My invention relates to mechanically driven means for comminuting and dividing materials which can be broken apart or divided finely by impacts and blows.

While hammer mills are well known for this purpose, they often cannot be operated in such a way as to reduce the intially fed material into the appropriate fineness or the appropriate sizes with a single handling in the hammer mill. Also, it is not always possible to provide for the operation of a hammer mill in such a way that the internal passages and compartments do not become clogged or jammed after short operation.

It is therefore an object of my invention to provide a hammer mill in which the fed material is treated a number of dilferent times in passing through the mill, but with only one handling.

Another object of the invention is to provide a hammer mill in which the mill is so arranged as to avoid clogging or jamming of the interior passages during operation.

Another object of the invention is to provide a hammer mill which can easily and quickly be constructed of substantially standard parts except for certain modifications to improve the operation of the mill.

Another object of the invention is to provide a hammer mill which requires no special instruction or operation in its working.

Another object is to provide a hammer mill that can readily be variably set for different operations.

A further object of the invention is to provide a hammer mill that is generally an improvement over hammer mills now available.

Other objects together with the foregoing are attained in the embodiment of the invention described in the accompanying description and disclosed in the accompanying drawings, in which:

FIGURE 1 is a cross section through portions of a hammer mill constructed in accordance with the invention, the several, generally horizontal planes of section being illustrated by the lines 1-1 of FIGURE 2; and

FIGURE 2 is likewise a cross section, but on vertical planes, of a hammer mill constructed pursuant to the invention, the planes of section being generally indicated by the lines 2-2 of FIGURE 1.

While the hammer mill of the invention can be embodied in a number of ditferent ways, it has successfully been incorporated in a practical form as shown herein. In this instance the hammer mill includes a generally upright frame 6 symmetrically disposed about a central axis 7 and appropriately mounted and supported. At the upper end of the frame 6 and leading toward a feed opening 8 therein is a feed hopper 9 of a generally conical configuration. This receives the material to be comminuated. -Appropriately disposed on the frame 6 is a vertical shaft 10 appropriately mounted in bearings 11 and mounted for rapid rotation about the axis 7 as a center. The shaft 10 is driven at proper speed by a conventional drive motor not illustrated.

Disposed on the shaft 10 is an elongated hub 16 preferably comprised of a number of sections fitted together for convenience in assembly and at appropriate intervals around the periphery carrying a number of individual pivot pins such as 17, 18, 19 and 20. These pins are all identical and extend in a vertical direction from 10- cations in the upper portion of the hub 16 with their 3,2l,28 5 Patented Nov. 23, 1965 axes parallel to the axis 7 to terminations adjacent the lower portion of the hub 16.

Provided in the hub 16 is a number of grooves 21 intersecting the bores for the pivot pins 17, 18, 19 and 20. These are arranged so that all of the grooves, or at least any selected grooves, can receive various ones of a number of identical hammers 22. These hammers are conveniently made of appropriate material formed in rectangular or strap-like configuration except that they are rounded at one end 23 concentrically with the associated pivot pins 17, 18, 19 or 20. The arrangement is such that the hammers 22 are supported for pivotal movement in horizontal planes, each hammer being quite free to rotate within wide limits about the axis of its respective one of the supporting pins 17, 18 19 and 20 but generally being impelled when otherwise unrestrained to lie radially with regard to the axis 7 under the influence of centrifugal force when the shaft 10 and the hub 16 rotate.

Particularly pursuant to the invention, not all of the grooves 21 are simultaneously supplied with hammers 22. As particularly illustrated in FIGURE 2, the hammers are preferably installed so that there is initially provided in the upper portion of the hub a first group of hammers A, B, C and D. This group is of four hammers counting axially in the present instance and includes four hammers counting radially, making a total of sixteen hammers in the first group. Instead of continuing this group, there is provided in addition a second, spaced group of hammers 22 adjacent the lower portion of the hub 16. In the second group are hammers E, F, G and H in each of the four radial positions, making another total of sixteen hammers in the second group.

Since a number of intervening slots 21 are left (in the present instance, sixteen slots are so vacant), there is provided between the lowermost hammer D of the first group and the uppermost hammer E of the second group an intervening annular compartment 26 concentric with the axis 7.

Located within the opening 8 at the upper part of the frame 6 is a collar 27 to which is fastened the appropriate portion of an upper screen 28 conveniently fabricated in halves and secured in position by fastenings 29 to bars 31 dependent from the collar 27. The upper or primary screen 28 when assembled extends from the collar 27 downwardly as a continuous cylinder to terminate in a reinforcing band 32 just under the lowermost of the hammers 22 in the first group. This screen 28 has openings of a predetermined size.

Somewhat similarly, there is provided a split lower or second screen 33 when assembled encompassing the hammers in the second group. The screen extends from a point just above the top hammers of the lower group to a point just below the lower hammers of the lower group. The secondary screen 33 has openings of a size preferably smaller than the openings in the primary screen 28. In practice, the ratio of the sizes of the screen openings is conveniently and usually established so as to distribute the relative loading of the rotor elements as preferred, for example, about evenly. A barrier 34 in the form of a plate mounted on a ring 36 secured to an inner band 37 serves as a barrier beneath the lowermost hammers 22 of the lower group. Also puruant to the invention, the upper or primary screen 28 and much of the intervening compartment 26 are surrounded or encompassed by a means for directing the material being handled. This means is in the form of a multi-part shield 41 conveniently of metal and having appropriate fastenings 42 to secure it in position on mounts 43 secured to the main frame 6. The shield 41 has a somewhat conical upper wall 44 inclined downwardly from its innermost portion adjacent the collar 27 to a line of junction with a circumferential band 46 almost exactly opposite the upper group of hammers 22. From the band 46 a lower conical plate 47 extends downwardly and inwardly to a terminatingbandAS surrouding the upper portion of and secured to the secondary screen 33.

In the operation of this structure, whentheshaft 10 is:rapidly rotated, *thehammers .22 initially assume their radially outward position. Material is then .fed into the hopper 9 and'proceeds-downwardly inthe general direction of the arrows 5 1 into the .upper portion of the mill. Material travelling downwardly encounters the uppergroup of hammers 22. It is partially comminuted by them andis discharged with aradially outward component to and throughthe primary screen Y28 and into-the volume '61 enclosed within the shield '41. This material, still travelling outwardly, is'then further comminutedby impact against the .walls. of the shield and is also directed generally downwardly and inwardly into ,the annular compartment 26.

Fromthe compartment 26 the material travelsgfurther inthe general direction of the arrows 51 and with an axial component into an encounter with the various hammersi-22 of :the second or lower group. Again, comminution takes place and the material again acquires a radial component. It is discharged in its more finely divided state through the secondary screen 33 into an :appropriate receiving volume within the 'frame 6. It is finally discharged after having been divided as desired.

In the operation of this device, the material which is initially fed into the hopper 9 is not only brought'into contact with;one groupof appropriately operatingjhammers, but :without further handling is, when divided, automatically directed inwardly in the direction opposite to its 'radial vdirection of propulsion for encounter with a second'group of communicating hammers. As it travels, it is doubly screwedand is divided bywall impact.

Since the hammers can 'be fitted in any ofthe slots, various patterns and arrangements are possible for optimum eifect on and best :handling of various feed materials. Thus the material 'by appropriate arrangement of thehammers within selected ones of the grooves 21 and by providing any desired number ,of groups and spacings of hammers and any appropriate number of screens and corresponding shields 41 can be discharged from the machine in the desired condition. Further, more, the direction of the material through the machine in encountering only individual groups of hammers at any one time and in being deflected by the appropriate surrounding shields is such that jamming and clogging of the machine do not occur.

What is claimed is:

1. A hammer mill comprising a frame, a shaftdisposed within said frame for rotation about a vertical axis, a hub on said shaft, a plurality of pivot pins disposed in said hub on axes parallel to said axis, a first group of hammers pivoted on said pivot pins a second group of hammers pivoted in saidtpivot pins and 'spaced'fromsaid first group to leave anzintervening annular compartment, a primary screen mounted on said frame and encompassing said first group of hammers, a secondary screen mounted on said frame and encompassing said second group of hammers, ffirst means 'for .directing :material axially into said first .group of hammers for radial discharge through said first screen, and second means on said frame and encompassing said first screen and said annular compartmentfordirecting all of said materialdischarged :through said firstscreenmadially in- .ward into saidcompartment and axially into said second groupof hammers.

2. A hammer mill as in claim :11 in .whichsaid-second means includes an annulargshield having a downwardly inclined conical lower Wall.

References Cited by the Examiner UNITED STATES'PATENTS 254,551 3/1882 Hottmann 241-76 293,047 2/1884 Mackey 241-76 1,212,418 1/1917 Sturtevant 24l-154 2,695,755 11/1954 Denovan et al. 24ll54 X 2,954,173 9/1960 DunWOdy 24l78XR 3,053,297 9/1962 Brundler 146-192 3,137,334 6/1964 Steele 146-192 ROBERT c. RIORDON, Primary Examiner.

:WILLIAM W. -DYER, :I. SPENCER OVERHOLZER,

Examiners. 

1. A HAMMER MILL COMPRISING A FRAME, A SHAFT DISPOSED WITHIN SAID FRAME FOR ROTATION ABOUT A VERTICAL AXIS, A HUB ON SAID SHAFT, A PLURALITY OF PIVOT PINS DISPOSED IN SAID HUB ON AXES PARALLEL TO SAID AXIS, A FIRST GROUP OF HAMMERS PIVOTED ON SAID PIVOT PINS, A SECOND GROUP OF HAMMERS PIVOTED IN SAID PIVOT PINS AND SPACED FROM SAID FIRST GROUP TO LEAVE AN INTERVENING ANNULAR COMPARTMENT, A PRIMARY SCREEN MOUNTED ON SAID FRAME AND ENCOMPASSING SAID FIRST GROUP OF HAMMERS, A SECONDARY SCREEN MOUNTED ON SAD FRAME AND ENCOMPASSING SAID SECOND GROUP OF HAMMERS, FIRST MEANS FOR DIRECTING MATERIAL AXIALLY INTO SAID FIRST GROUP OF HAMMERS FOR RADIAL DISCHARGE THROUGH SAID FIRST SCREEN, AND SECOND MEANS ON SAID FRAME AND ENCOMPASSING SAID FIRST SCREEN AND SAID ANNULAR COMPARTMENT FOR DIRECTING ALL OF SAID MATERIAL DISCHARGED THROUGH SAID FIRST SCREEN RADIALLY INWARD INTO SAID COMPARTMENT AND AXIALLY INTO SAID SECOND GROUP OF HAMMERS. 